After watching "The Vampires of Venice," a bit of a mini-theme is starting to emerge in this season of Doctor Who: the Doctor having to choose between humans and other intelligent species. What gives him the right? Spoilers below.

Sometimes on Doctor Who, the choice is pretty clear-cut. The nasty Sontarans come barreling down and try to poison the whole human race just so they can use Earth as a breeding planet? It's not hard to pick a side. But consider this season.

In "The Beast Below," the Doctor is faced - temporarily, thank goodness - with a choice between dooming some of the human race's last survivors, versus freeing an ancient, intelligent life form from slavery and torment. And now in "The Vampires of Venice," those alleged vampires (actually fish creatures) make a strong case that they deserve to go on living as well — all they want is to take over one small, water-logged city. And then there's the fact that - spoiler alert - an adventure is coming up featuring the Silurians, who have as much of a claim on the planet Earth as we do.

So it's not that every story this season has featured this theme, but a few of them have. It's sort of interesting as one of the threads percolating in a season that's all about the Doctor and Amy apparently bringing chaos in their wake. Or maybe instead, it's the Doctor and Amy traipsing through a universe where nothing is stable and everything can be rewritten. There's only one constant point in all of this scary flux: the Doctor will always choose humans over everyone else. Or will he?

It's interesting to think back to the first season of the renovated Doctor Who, when the Doctor was willing to let the Gelth reanimate all of the corpses in Victorian London, just because the Gelth had a right to survive as well. Sure, Rose's history books might not have shown Dickensian London being overrun with Gelth zombies, but the sanctity of human history doesn't count for as much as the Gelth's right to survive.

Of course, the right of the Saturnynians to survive is only raised as a sort of afterthought towards the end of "Vampires of Venice," although I expect these sorts of issues to get more play in the upcoming Silurian two-parter. Most of the story is structured as a pretty standard "running from alien monsters" romp. The Doctor takes Amy and Rory to Venice as a wedding present (and to help them re-bond after Amy jumped on the Doctor last week.) So Amy and Rory process their feelings while coping with the menace of the fish-people (subtle crossover with "The Underwater Menace" here) and Amy goes undercover as a vestal virgin student at the fish-vampire academy.

And really "The Vampires of Venice" is similar to "School Reunion" — the story that writer Toby Whithouse wrote back in season two. The plot is wafer thin (I've seen "School Reunion" three times, and I still couldn't tell you what Anthony Stewart Head was trying to do. It was something to do with making kids do math) but it's really about the companion spending time with someone who challenges her worldview. Last time, it was Rose meeting former companion Sarah Jane Smith, and this time it's Amy's boyfriend Rory, who's having his bachelor party the night before their wedding, and is shocked to realize Amy's been traveling with the Doctor for ages. Rory represents the pull for Amy to settle down and give up her vagabond dreams for marriage and stability. Amy's meant to be torn between the Doctor and Rory, and in the end she manages to choose them both and they become "her boys."

But returning to the question of the Doctor choosing the human race over all the various alien races who also have a right to survive, Rory is kind of the representative of humanity in this episode. Amy's been traveling with the Doctor long enough that she's already gotten slightly more jaded and detached - she's excited at the idea of meeting vampires, while Rory reacts the way a normal person would. He's much closer to being an Everyman-type character in this episode, gawping at all the weirdness and scary monsters. So even while Amy is choosing between Rory and the Doctor, the Doctor in a sense is choosing between Rory and the fish monsters.

And at least in this episode, Rory is a bit underwhelming. He's struggling to break out of the Mickey Smith box. You start to wonder why Amy would be into him. It's only towards the end of the episode, when Rory begins to act a bit more valiant, that you can see why he's worthy of being a companion, and not just the guy that Amy leaves behind to go on her adventures. Here's hoping that Rory starts showing a bit more awesomeness - we need to see why we humans deserve the Doctor's favoritism.